This invention relates to a casting unit for the manufacturing of a plurality of cast parts by directed solidification or monocrystal formation using a mold shell comprising a plurality of individual molds corresponding to the cast parts, and having a cooling plate which forms a lower end of the mold shell, as well as to a process using such a casting unit.
A casting unit of this type is known from the European Patent Document EP-A-0 477 136. In this patent document, a casting unit is described in the case of which the individual cast parts are arranged in a cluster form in a circular shape around a central trunk. By means of the centric arrangement of the individual molds, it is ensured that the same conditions exist for all cast parts with respect to the thermal economy during the solidification and thus the directing of the solidification front is the same in each cast part. As a result, the same quality can be achieved for each cast part.
It is a disadvantage of the known casting unit that, when the number of individual molds per casting unit is to be increased in order to increase the economy during the casting, the diameter of the casting unit must be increased, which requires larger and therefore more expensive furnaces. On the other hand, a free space is created in the interior of the circularly arranged individual molds which is not utilized. If individual molds were to be arranged also in this inner free space, the requirement of the same thermal economy for all individual molds or cast parts during the solidification could not easily be met. For solving this problem, the U.S. Pat. No. 3,763,926 teaches the cooling of the individual molds using a tin melt which, however, causes considerable manufacturing expenditures.
There is therefore needed a casting unit of the above-mentioned construction in the case of which a number of cast parts that is as large as possible can be manufactured simultaneously and with low constructional expenditures.